The thumb piano, or kalimba, may go back thousands of years but in the hands of new media musician Leung Kei-cheuk, also known as GayBird, this ancient African musical instrument becomes something of the future.

The Signal Pipe, as he calls his modified version, produces not only different pitches but real-time visuals that can be projected onto a big screen when the iron bars are plucked.

"New media is a way for us to detect the future of music," says Leung, who graduated from the Hong Kong Academy for Performing Arts with a specialisation in music composition and electro-acoustics.

"Music and technology have always been closely related. Think how the development in woodcraft helps improve a piano's dynamics, for instance, or how the invention of pick-ups for guitars gave rise to rock.

"I'm always searching for new ways to present music. To achieve that, the first thing I have to do is create new musical instruments," he says.

The Signal Pipe is among a number of interactive musical instruments that Leung will play at his upcoming audio-visual show CouCou on Mars at City Hall. The artist says "CouCou" (an informal "hello" in French and the sound of a cuckoo clock) represents our daily lives on earth while Mars symbolises the future.

Leung has also designed several "wristwatches", which instead of telling the time, feature buttons that create different sounds. And when they are connected to another "watch" with a retractable chord, the sound created will be affected by the distance and movements between the wearers.

"I prefer to call my creations 'visual music'. Many artists do new media music work behind the monitor of a laptop so the audience wouldn't know what's happening. And it seldom involves body language, which I think is crucial in a music performance," says Leung. "I want people to see me playing. I want my performance to be understood - they don't just hear the music, they should be able to see for themselves how it's operated and created."

The show is the result of a collective effort from his hi-tech friends and their skills in art, technology and mechanics. They include Justin Wong Chiu-tat (a lecturer at the academy), who is responsible for comic and video design, along with Henry Chu Lik-hang and Thomas Ip Kwok-tung who performed apps design, programming and engineering, among other tasks.

Leung has mixed technology and music for audiences before, in his award-winning 2011 show Digital Hug. More innovations can be expected at his latest concert, where Japanese singer-songwriter Kaori Hasegawa, known by her stage name UA, will be a special guest singer. And her voice, of course, is set to trigger a series of visual surprises as well.